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optimize config_read() (by Timo Teras <timo.teras AT iki.fi>)

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function                                             old     new   delta
bb_get_chunk_with_continuation                         -     176    +176
find_pair                                            169     187     +18
...
process_stdin                                        443     433     -10
config_read                                          549     456     -93
bb_get_chunk_from_file                               139       7    -132
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 7/7 up/down: 215/-254)          Total: -39 bytes
This commit is contained in:
Denis Vlasenko 2008-08-09 17:16:40 +00:00
parent 3fd15e197e
commit 69f4f9a6f4
3 changed files with 93 additions and 117 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/libbb.h
View File

@ -613,6 +613,7 @@ extern void xopen_xwrite_close(const char* file, const char *str) FAST_FUNC;
extern void xprint_and_close_file(FILE *file) FAST_FUNC;
extern char *bb_get_chunk_from_file(FILE *file, int *end) FAST_FUNC;
extern char *bb_get_chunk_with_continuation(FILE *file, int *end, int *lineno) FAST_FUNC;
/* Reads up to (and including) TERMINATING_STRING: */
extern char *xmalloc_fgets_str(FILE *file, const char *terminating_string) FAST_FUNC;
/* Chops off TERMINATING_STRING from the end: */

30
libbb/get_line_from_file.c
View File

@ -9,18 +9,22 @@
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
/* for getline() [GNUism] */
/* for getline() [GNUism]
#ifndef _GNU_SOURCE
#define _GNU_SOURCE 1
#endif
*/
#include "libbb.h"
/* This function reads an entire line from a text file, up to a newline
* or NUL byte, inclusive. It returns a malloc'ed char * which
* must be free'ed by the caller. If end is NULL '\n' isn't considered
* end of line. If end isn't NULL, length of the chunk read is stored in it.
* Return NULL if EOF/error */
char* FAST_FUNC bb_get_chunk_from_file(FILE *file, int *end)
* end of line. If end isn't NULL, length of the chunk is stored in it.
* If lineno is not NULL, *lineno is incremented for each line,
* and also trailing '\' is recognized as line continuation.
*
* Returns NULL if EOF/error. */
char* FAST_FUNC bb_get_chunk_with_continuation(FILE *file, int *end, int *lineno)
{
int ch;
int idx = 0;
@ -30,12 +34,20 @@ char* FAST_FUNC bb_get_chunk_from_file(FILE *file, int *end)
while ((ch = getc(file)) != EOF) {
/* grow the line buffer as necessary */
if (idx >= linebufsz) {
linebufsz += 80;
linebufsz += 256;
linebuf = xrealloc(linebuf, linebufsz);
}
linebuf[idx++] = (char) ch;
if (!ch || (end && ch == '\n'))
if (!ch)
break;
if (end && ch == '\n') {
if (lineno == NULL)
break;
(*lineno)++;
if (idx < 2 || linebuf[idx-2] != '\\')
break;
idx -= 2;
}
}
if (end)
*end = idx;
@ -52,6 +64,11 @@ char* FAST_FUNC bb_get_chunk_from_file(FILE *file, int *end)
return linebuf;
}
char* FAST_FUNC bb_get_chunk_from_file(FILE *file, int *end)
{
return bb_get_chunk_with_continuation(file, end, NULL);
}
/* Get line, including trailing \n if any */
char* FAST_FUNC xmalloc_fgets(FILE *file)
{
@ -72,7 +89,6 @@ char* FAST_FUNC xmalloc_fgetline(FILE *file)
}
#if 0
/* GNUism getline() should be faster (not tested) than a loop with fgetc */
/* Get line, including trailing \n if any */

179
libbb/parse_config.c
View File

@ -123,137 +123,96 @@ mintokens > 0 make config_read() print error message if less than mintokens
#undef config_read
int FAST_FUNC config_read(parser_t *parser, char **tokens, unsigned flags, const char *delims)
{
char *line, *q;
char comment;
int ii;
int ntokens;
int mintokens;
char *line;
int ntokens, mintokens;
int t, len;
comment = *delims++;
ntokens = flags & 0xFF;
mintokens = (flags & 0xFF00) >> 8;
again:
memset(tokens, 0, sizeof(tokens[0]) * ntokens);
if (!parser)
if (parser == NULL)
return 0;
again:
memset(tokens, 0, sizeof(tokens[0]) * ntokens);
config_free_data(parser);
while (1) {
//TODO: speed up xmalloc_fgetline by internally using fgets, not fgetc
line = xmalloc_fgetline(parser->fp);
if (!line)
return 0;
/* Read one line (handling continuations with backslash) */
line = bb_get_chunk_with_continuation(parser->fp, &len, &parser->lineno);
if (line == NULL)
return 0;
parser->line = line;
parser->lineno++;
// handle continuations. Tito's code stolen :)
while (1) {
ii = strlen(line);
if (!ii)
goto next_line;
if (line[ii - 1] != '\\')
break;
// multi-line object
line[--ii] = '\0';
//TODO: add xmalloc_fgetline-like iface but with appending to existing str
q = xmalloc_fgetline(parser->fp);
if (!q)
break;
parser->lineno++;
line = xasprintf("%s%s", line, q);
free(q);
}
// discard comments
if (comment) {
q = strchrnul(line, comment);
*q = '\0';
ii = q - line;
}
// skip leading and trailing delimiters
if (flags & PARSE_TRIM) {
// skip leading
int n = strspn(line, delims);
if (n) {
ii -= n;
overlapping_strcpy(line, line + n);
}
// cut trailing
if (ii) {
while (strchr(delims, line[--ii]))
continue;
line[++ii] = '\0';
}
}
// if something still remains -> return it
if (ii)
break;
/* Strip trailing line-feed if any */
if (len && line[len-1] == '\n')
line[len-1] = '\0';
next_line:
// skip empty line
free(line);
}
// non-empty line found, parse and return the number of tokens
/* Skip token in the start of line? */
if (flags & PARSE_TRIM)
line += strspn(line, delims + 1);
// store line
parser->line = line = xrealloc(line, ii + 1);
if (flags & PARSE_KEEP_COPY) {
if (line[0] == '\0' || line[0] == delims[0])
goto again;
if (flags & PARSE_KEEP_COPY)
parser->data = xstrdup(line);
}
// split line to tokens
ntokens--; // now it's max allowed token no
// N.B. non-empty remainder is also a token,
// so if ntokens <= 1, we just return the whole line
// N.B. if PARSE_GREEDY is set the remainder of the line is stuck to the last token
ii = 0;
while (*line && ii <= ntokens) {
//bb_info_msg("L[%s]", line);
// get next token
// at last token and need greedy token ->
if ((flags & PARSE_GREEDY) && (ii == ntokens)) {
// skip possible delimiters
if (flags & PARSE_COLLAPSE)
line += strspn(line, delims);
// don't cut the line
q = line + strlen(line);
/* Tokenize the line */
for (t = 0; *line && *line != delims[0] && t < ntokens; t++) {
/* Pin token */
tokens[t] = line;
/* Combine remaining arguments? */
if ((t != (ntokens-1)) || !(flags & PARSE_GREEDY)) {
/* Vanilla token, find next delimiter */
line += strcspn(line, delims[0] ? delims : delims + 1);
} else {
// vanilla token. cut the line at the first delim
q = line + strcspn(line, delims);
if (*q) // watch out: do not step past the line end!
*q++ = '\0';
}
// pin token
if (!(flags & (PARSE_COLLAPSE | PARSE_TRIM)) || *line) {
//bb_info_msg("N[%d] T[%s]", ii, line);
tokens[ii++] = line;
// process escapes in token
#if 0 // unused so far
if (flags & PARSE_ESCAPE) {
char *s = line;
while (*s) {
if (*s == '\\') {
s++;
*line++ = bb_process_escape_sequence((const char **)&s);
} else {
*line++ = *s++;
}
}
*line = '\0';
/* Combining, find comment char if any */
line = strchrnul(line, delims[0]);
/* Trim any extra delimiters from the end */
if (flags & PARSE_TRIM) {
while (strchr(delims + 1, line[-1]) != NULL)
line--;
}
#endif
}
line = q;
//bb_info_msg("A[%s]", line);
/* Token not terminated? */
if (line[0] == delims[0])
*line = '\0';
else if (line[0] != '\0')
*(line++) = '\0';
#if 0 /* unused so far */
if (flags & PARSE_ESCAPE) {
const char *from;
char *to;
from = to = tokens[t];
while (*from) {
if (*from == '\\') {
from++;
*to++ = bb_process_escape_sequence(&from);
} else {
*to++ = *from++;
}
}
*to = '\0';
}
#endif
/* Skip possible delimiters */
if (flags & PARSE_COLLAPSE)
line += strspn(line, delims + 1);
}
if (ii < mintokens) {
if (t < mintokens) {
bb_error_msg("bad line %u: %d tokens found, %d needed",
parser->lineno, ii, mintokens);
parser->lineno, t, mintokens);
if (flags & PARSE_MIN_DIE)
xfunc_die();
ntokens++;
goto again;
}
return ii;
return t;
}